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• Co doped MoS 2 was decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) by a solvothermal process. • The lattice spacing of (1 0 0) plane of Co-MoS 2 was slightly narrow than that of MoS 2. • The as-prepared Co-MoS 2 /NCFCP hybrids showed enhanced electrochemical activity for HER. In this paper, Co-doped MoS 2 (Co-MoS 2) with various Co/Mo mole ratio (6%–12%) decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) (Co-MoS 2 /NCFCP) is fabricated by a solvothermal method as an efficient electrocatalyst for hydrogen evolution reaction (HER). The NCFCP substrate is prepared by electrochemical deposition of polypyrrole on carbon paper followed by heat treatment. The obtained 9% Co-MoS 2 /NCFCP hybrid catalyst exhibits an excellent electrocatalytic HER activity with a low overpotential of 174 mV at 10 mA cm−2, a small Tafel slope of 52 mV dec−1 and long-term stability. Thus, Co-MoS 2 /NCFCP hybrid holds high potential as an efficient earth-abundant electrocatalyst material for HER. [ABSTRACT FROM AUTHOR]

In this paper, we present a solvothermal synthesis of iron phosphide electrocatalysts using a triphenylphosphine (TPP) precursor. The synthetic protocol generates Fe 2 P phase at 300 °C and FeP phase at 350 °C. To enhance the catalytic activities of obtained iron phosphide particles heat-treatments were carried out at elevated temperatures. Annealing at 500 °C under reductive atmosphere induced structural changes in the samples: (i) Fe 2 P provided a pure Fe 3 P phase (Fe 3 P−500 °C) and (ii) FeP transformed into a mixture of iron phosphide phases (Fe 2 P/FeP−500 °C). Pure Fe 2 P films was prepared under argon atmosphere at 450 °C (Fe 2 P−450 °C). The electrocatalytic activities of heat-treated Fe 2 P−450 °C, Fe 3 P−500 °C, and Fe 2 P/FeP−500 °C catalysts were studied for hydrogen evolution reaction (HER) in 0.5 M H 2 SO 4. The HER activities of the iron phosphide catalyst were found to be phase dependent. The lowest electrode potential of 110 mV vs. a reversible hydrogen electrode (RHE) at 10 mA cm−2 was achieved with Fe 2 P/FeP−500 °C catalyst. Image 1 • Iron phosphides catalyst were synthesized via a wet-chemistry method. • Spin-coating of iron phosphide particles onto graphite substrates yielded uniform thin films. • Heat treatment of iron phosphides at 500 °C resulted in structural changes. • The iron phosphide films were used as electrocatalysts for efficient hydrogen evolution. [ABSTRACT FROM AUTHOR]